Shotgun muzzle device



Patented Aug. 17, 1948 NITED STATE P This invention has reference todevices of the type known as compensator-type chokes for shotguns: thegeneral purpose and object of the in- }vention is to provide bettercontrol of shot pattern than has heretofore been achieved, to attainhigher shot velocities than have been practicable with knowncompensator-type chokes, to minimize recoil and to control or reducemuzzle jump and muzzle blast of the gun. These and other objects,together with the corresponding accomplishments of the invention willappear in the following.

Shot-gun compensator-type chokes commonly in present use embody acylindric perforated cage which projects forwardly from a-shortened gunbarrel, with a choke tube mounted in the forward end of the cage andprojecting forwardly from it.

The cage is of larger diameter than the barrel and is of such lengththat the rear'or pickup" end of the choke tube is commonly locatedseveral inches forward of the barrel muzzle. The gap between the barrelmuzzle and the choke tube is considerably longer than the total lengthof the shot charge and the following wad; so that the wad leaves the gunmuzzle before the shot charge enters the rear or pick-up end of thechoke tube. The high pressure gases which are released when the wadleaves the muzzle may thus flow forwardly through the cage around theshot charge and, travelling at higher velocity than that charge, enterthe choke tube ahead of the charge. In that action the high velocitygases tend to disturb the solid mass arrangement of the shot. Also theshot charge tends to expand laterally as soon as it leaves the muzzleand must be gathered together, or laterally recompressed by the pick-upend of the choke tube.

The general result is that, although a considshot gun chokes of thetypes now in use (cages with longitudinal or circumferential slotsdistributed around the cage wall, or with an even distribution ofperforations around the wall) may be used with my inside type choketubes. However I prefer to provide a cage of a design here- 2 inafterdescribed for the purpose of minimizing recoil and muzzle jump.

The choke tube of my choke device is mounted in the forward end of thecage but extends rearwardly from that forward end toward the gun muzzle,leaving only a short annular gap between the gun muzzle and the rear endof the choke tube. This short annular gap provides an escape port for acontrollably limited amount of the high pressure, high velocity; ases,which then flow forwardly around the choke tube and find ultimate exitthrough the opening or openings in the cage wall, in the manner whichwill be described. The gap between gun muzzle and choke tube may bevaried in its axial dimension, but in every case it is always muchshorter than the total axial length dimension of the shot charge andwad. Infact, this gap dimension will not ordinarily be much if anylonger than the axial dimension of the wad. In any event, the shotcharge always enters the choke tube a substantial distance, if not forthe whole length of the shot charge, before the wad leaves the muzzle.The wad thus effectively holds back the high velocity gases which wouldotherwise tend to by-pass the charge if the charge had not en: tered thechoke tube by the time the wad leaves the muzzle; the charge is thuskept in a compact mass and the high velocity gases which are notlaterally relieved follow the shot charge and wad through the choketube. This followin action, together with the fact that with myrelatively short choke device the gun barrel itself may be longer thanis commonly the casewith the pres ent long choke devices, gives the shotcharge a materially higher muzzle velocity than is at present achievedwith chokes. Also, the shortness of the gap afiords the shot charge verylittle opportunity to spread laterally, and consequently, the shotcharge does not have to be recompressed laterally, with attendantdisturbances of the mass and deformation of pellets, upon entering the.

' choke tube.

The invention will be more fully understood from the following detaileddescription or a preferred embodiment shown in the accompanying drawingsin which Fig. 1 is a longitudinal central section showing my presentpreferred form of choke mounted upon the end of a shot gun barrel, thisfigure showing the charge in a position entering the choke tube;

Fig. 2 is a similar view showing the charge and wad in the choke tube,and

Fig. 3 is a cross-section on line 3-3 of Fig. i.

. in the drawings the muzzle end portion of a shot gun is shown at it,the extreme muzzle end being designated by the numeral H. The muzzle endis provided externally with screw-threads l2, or any other suitableattaching means by which the tubular cage i5 is mounted upon the muzzleend of the barrel to project forwardly therefrom in the manner shown.The case as here shown has a cylindric wall l6 with an opening I! at oneside only. The purpose of. this single opening through one side only ofthe wall will be explained later. But, as I have said, wall I 6 of thecage may be equipped with final outlet openings of any suitable type,character, and

pattern. As here shown, outlet I! is of elongated rectangular form.

The outer end of cage i5 is internally screwthread'ed at til, orotherwise formed for the convenient mounting of the choke tube which isgenerally designated by the numeral 2|. As here shown, the choke tube isprovided, at or near its outer end, with threads matching the threads20, and with a shoulder 22 which may be butted against the outer end ofcase it. The choke tube extends rearwardly or inwardly in the cage, andits inner end, designated by the numeral 23, is located at a relativelyshort distance from muzzle end I l of the barrel, so that an annularescape port of limited'axial length is provided between the muzzle endand inner end 23 of the choke tube. The internal diameter of the mainbore 25 of the choke tube is preferably the same as that of the bore ofbarrel ill. The choke formatlon, shown at 26 at the forward end of thechoke tube may be of any desired configuration, and choke tubes withdifferent choke configurations may be substituted in the cage.

As shown in the drawings, the internal diamstar of cylindric cage i5 issubstantially larger than the bore diameter of the gun and alsosubstantially larger than the external diameter of choke tube 2!. Thus,an annular passage 21 is left between cage wall i6 and the exterior ofthe choke tube, that annular passage being closed at its forward end bythe shoulder which is shown at 28. Outlet opening I I has its outer endat that shoulder 28, and has its inner end 29 in about the sametransverse plane as the inner end 23 of choke tube 2 I.

Without limiting my invention thereto, I give the f ollowing typicaldimensions for my choke device as applied to a 12-gage shot gun. Thedrawlogs are approximately full scale for that size of gun. For such agun, which has a bore of about 0.75", the internal diameter of cage I5is here shown as being about 1.25". The length of the cage from muzzleend H to shoulder 28 is shown as about 3%; the total length of the choketube is about 3 /2, the gap between the barrel muzzle and the choke tubeis shown as being 0.5" and the outlet port H as being about 0.75" Wideand about 2%" long. The maximum external diameterof the part of thechoke tube which defines one wall of annular passage 27 is about 1",making that annular passage have a radial dimension of about Va". Thewell of the choke tube may be tapered in thickness from its threads tothe inner end 23, as shown.

Fig. 1 shows how the shot charge of any ordinary volume (say about 1" inlength) will bridge the annular gap at G so that the shot charge hasentered some distance forwardlyinto the rear end of choke tube 2i whilethe wad W is still in gun barrel ii). Thus, before wad W leaves the gunbarrel, shot charge S has almost completely, if

not completely, entered the choke tube and has effectively sealed thechoke tube against being by-passed by the following gases from the gunbarrel.

Fig. 2 shows shot charge 8 and wad W completely in the choke tube, andwith the annular opening or port at G completely open. As soon as wad Wleaves the muzzle end II, the following gases begin to now laterallythrough the annular gap at G and into the annular passage 21 betweencage wail l6 and choke tube 2|. The proportionate part of the gaseswhich flow through the annular gap and flow outwardly through annularpassage 21 is determined and controlled by the length .of gap G. Thegases which do not flow through gap G follow the charge and wad throughthe choke tube, adding velocity to the charge.

The gases which do flow through the annular gap at G flow forwardlythrough annular passage 21 and laterally toward the outlet port H, inmuch the pattern of flow which is indicated by the arrows in Fig. 2. Theforwardly flowing gases are turned laterally by the shoulder 28, and theforward longitudinal force which is thus exerted on that shoulder tendsmaterially to diminish the recoil action of the gun. Finally, thelateral flow of the gases through port I! tends to move the gun muzzlelaterally in the opposite direction. By placing the device upon the gunin such a position that outlet port I! is upward (that is, port I! is atthe top of the device when in use) the lateral reaction of the escapinggases is in a downward direction and tends very materially" to minimizethe upward jump of the gun muzzle.

As has been indicated, the proportionate amount of the gases releasedthrough the annular gap at G depends upon and is controlled by the axiallength of that gap; and that axial length may be proportioned to releasea lesser or lar er fraction of the whole gaseous charge. However,

, in any case, the axial length of G is always considerably less thanthe total axial length of shot charge S and Wild W, so that the gasescannot by-pass the shot charge. The area of the annular gap at G havingbeen determined (inthe present design that area is something over twicethe circular area of the barrel bore) then the total area of outlet portI! is made to ,be about the same as the area at gap G, or somewhatsubstantially larger. As here shown the annular area of the port at G isabout 1.18 sq. in. and the area of port I1 is about 2 sq. in. And thecross-sectional area of annular passage 21, as here shown, maypreferably be substantially smaller than the total area at annular gapG, so that the gases flow forwardly through annular passage 2'! at afairly high velocity to be turned laterally by the shoulder at 28. Asshown, the cross-sectional area of the annular passage is about the sameas that of the gun bore or of the interior of the choke tube at itsrearward end-0.442 sq. in.

' I claim:

1. A muzzle device for firearms of the shot gun type discharging ascatter shot charge, which includes a substantially tubular cage, meansfor mounting the rear end of said cage on and surrounding the muzzle ofa gun barrel to which the device is designed to be attached, a shotpattern control tube supported and extending longitudinally within saidcage and adapted to terminate in spaced relation from the muzzle end ofthe' 70 following wad normally designed for the gun, said aeeaaoe d cageand tube being constructed and arranged to provide a passage extendinglongitudinally between them and in open communication with said gap, andoutlet means in the wall of said cage leading exteriorly from saidpassage to the atmosphere.

2. A muzzle device as specified in claim 1 in which the wall of saidshot pattern control tube is imperforate.

3. A muzzle device as specified in claim 1, comprising means forsupporting said shot pattern control tube at a location near the forwardend of said cage and for closing the forward end of said passage.

4. A muzzle device as specified in claim 1, in which the wall of saidshot pattern control tube is imperforate, said tube having threadedengagement within the forward end of the cage, an integral forwardlyfacing shoulder on the cage, and a rearwardly facing shoulder on thetube engageable against said cage shoulder.

5. The combination comprising a shot gun barrel, and a muzzle devicecarried by the barrel, said device including a substantially tubularcage having its rear end secured to and about the muzzle end of saidbarrel, a shot pattern control tube supported within said cagesubstantially in alinement with the barrel and terminating in spacedrelation from the muzzle end of the barrel to form a gap the length ofwhich is not more than the total axial length of a shot charge andfollowing wad designed for the gun, said cage and tube being constructedand arranged to provide a passage extending longitudinally between themand in open communication with said gap, and outlet means in the wall ofsaid cage leading exteriorly from said passage to the atmosphere.

6. A muzzle device as specified in claim 5, also including means fordetachably securing the shot pattern control tube at a location in theforward end portion of the cage and from which the tube projectsrearw-ardly toward the barrel.

'7. A muzzle device as specified in claim 5, in which said shot patterncontrol tube is imperferate, and further including a threaded connectionbetween the tube "and forward end portion of the cage, and an annularshoulder on the tube engageable against the cage.

8. A muzzle device as specified in claim. 5, in which said tube isimperforate and is supported only within the forward end portion of thecage.

EDWARD BADEN POWELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,080,154 Moore Dec. 2, 19131,860,276 De Luce et a1 May 24, 1932 1,901,138 Barnes Mar. 14, 19331,939,700 Hofstetter Dec. 19, 1933 2,112,831 Cutts Apr. 5, 19382,348,114 Dow May 2, 1944 2,372,315 Catron Mar. 27, 1945

